The thorax or chest cavity of a person contains the lungs and mediastinum which holds the heart and major vessels. The lungs are retained within a pair of airtight pleural cavities within the thorax. Respiration occurs as the result of a partial vacuum being maintained within each of these pleural cavities.
When we breathe in, our muscles cause the chest walls to move out and our diaphragm at the lower portion of the thorax to move down. This increases the volume of the thorax and pleural cavities, resulting in a corresponding pressure drop. The lungs, being exposed to greater atmospheric pressure through airways to the mouth or nose, expand with air to fill the increasing volume and equalize the pressure difference. When a person breathes out, the chest walls move in and the diaphragm moves up which squeezes the lungs and forces air from the lungs through the airways.
The lungs have no muscles or other control of their own to keep them in an expanded condition. The only means of lung expansion is the partial vacuum which is created when the chest wall moves out and the diaphragm moves down. If the partial vacuum is released or not able to be maintained, there is nothing to expand the lung, and it collapses. Pneumothorax is the condition where air or other gas is present in at least one of the pleural cavities which prevents expansion of a lung. It occurs spontaneously as a result of disease, injury or lung tissue, or puncture of the chest wall. If the partial vacuum is not restored to the pleural cavities, pneumothorax can be fatal.
A number of methods and devices are available for treating pneumothorax. One method requires the making of an incision between a pair of ribs and inserting a chest tube into the affected pleural cavity. The tube is then connected to a vacuum source for evacuating the cavity to enable the patient to breathe while the cause and ultimate treatment for the pneumothorax are determined. Another method employs the insertion of a needle into the affected pleural cavity and connecting the needle by a long tube to a one-way valve device which enables exhausting of air from the pleural cavity and prevents air from re-entering the pleural cavity. Yet another method employs use of a conventional hypodermic syringe for aspirating air from a pleural cavity using the syringe plunger.
These and other present accepted methods are not without drawbacks. For example, it can be difficult and time consuming to properly insert the chest tube. Specialized equipment is not always readily available and, when available, requires extreme care in use. Additionally, most current products require different sized apparatuses for use on different size patients. Further, most of the specialized products are costly.
A need remains for an improved device for providing immediate temporary treatment of pneumothorax.